Capacitive sensor electrode

Abstract

A capacitive electrode has a flat electrode with a geometric shape, wherein at least one central portion of the electrode is removed to provide for a frame-like form of the electrode.

What is claimed is: 
     
       1. A capacitive sensor structure comprising a sensing area having a width and length, wherein the capacitive sensor structure comprises:
 a plurality of capacitive electrodes, each capacitive electrode comprising:
 a rectangular electrode base section and 
 a plurality of rectangular electrode cross sections, 
 wherein the entire central portion of the rectangular electrode base section and the entire central portion of each electrode cross section is removed thereby providing for a base frame section and a plurality of cross frame sections, 
 wherein the electrode is formed by the base frame section which substantially extends over the width of the sensing area and the plurality of cross frame sections which are symmetrically arranged to cross the rectangular base section and are spaced apart along the width of the sensing area, wherein the plurality of capacitive electrodes are arranged within a first layer and wherein the base sections of the plurality of capacitive electrodes are arranged in parallel; and 
 
 wherein each capacitive electrode is further configured to be connected with a connecting line and wherein the connecting line extends through a center of the base frame section from a top to a bottom of the base frame section along the width of the sensing area. 
 
     
     
       2. The capacitive sensor structure according to  claim 1 , comprising a second layer of capacitive electrodes arranged perpendicular to the base frame sections of said capacitive electrodes of the first layer, wherein first and second layer are insulated by a substrate. 
     
     
       3. The capacitive sensor structure according to  claim 2 , wherein center electrodes of the second layer capacitive electrodes comprise a rectangular base section substantially extending from a left to a right side along a length of the sensing area and a plurality of finger sections from a top and bottom side of the rectangular base section. 
     
     
       4. The capacitive sensor structure according to  claim 2 , wherein top and bottom electrode of the second layer capacitive electrodes comprise a rectangular base section substantially extending from the left to the right side along the length of the sensing area and a plurality of finger sections from a top or bottom side of the rectangular base section, respectively. 
     
     
       5. The capacitive sensor structure according to  claim 3 , wherein adjacent capacitive electrodes of the second layer are arranged in an interdigital fashion with respect to the finger sections. 
     
     
       6. A capacitive sensor structure comprising a sensing area having a width and length, wherein the capacitive sensor structure comprises:
 a plurality of capacitive electrodes, each capacitive electrode comprising:
 a rectangular electrode base section and 
 a plurality of rectangular electrode cross sections, 
 wherein the entire central portion of the rectangular electrode base section and the entire central portion of each electrode cross section is removed thereby providing for a base frame section and a plurality of cross frame sections, 
 wherein the electrode is formed by the base frame section which substantially extends over the width of the sensing area and the plurality of cross frame sections which are symmetrically arranged to cross the rectangular base section and are spaced apart along the width of the sensing area, wherein the plurality of capacitive electrodes are arranged within a first layer and wherein the base sections of the plurality of capacitive electrodes are arranged in parallel; and 
 
 wherein the cross frame sections of adjacent capacitive electrodes are offset with respect to the width of the sensing area and adjacent capacitive electrodes are arranged in inter-digital fashion with respect to the cross frame sections, 
 wherein each capacitive electrode is further configured to be connected with a connecting line and wherein the connecting line extends through a center of the base frame section from a top to a bottom of the base frame section along the width of the sensing area. 
 
     
     
       7. The capacitive sensor structure according to  claim 6 , wherein cross frame sections of adjacent capacitive electrodes provide for a mutual capacitance between adjacent capacitive electrodes. 
     
     
       8. The capacitive sensor structure according to  claim 1 , wherein each capacitive electrode is formed by a layer of Indium Tin Oxide (ITO) on plastic film or glass. 
     
     
       9. The capacitive sensor structure according to  claim 1 , wherein each capacitive electrode is formed by a layer of electrically conductive material on a substrate. 
     
     
       10. The capacitive sensor structure according to  claim 1 , wherein a thickness of a frame defines a capacitive parameter of each capacitive electrode, the frame comprising the base frame section and the plurality of cross frame sections. 
     
     
       11. A capacitive sensor structure comprising a sensing area having a width and length, wherein the capacitive sensor structure comprises a first plurality of capacitive electrodes, each capacitive electrode of the first plurality of capacitive electrodes comprising a rectangular electrode base section and a plurality of rectangular electrode cross sections, wherein the entire central portion of the rectangular electrode base section and the entire central portion of each electrode cross section is removed thereby providing for a base frame section and a plurality of cross frame sections, wherein the electrode is formed by the base frame section which substantially extends over the width of the sensing area and the plurality of cross frame sections which are symmetrically arranged to cross the rectangular base section and are spaced apart along the width of the sensing area,
 wherein the first plurality of capacitive electrodes are arranged within a first layer and wherein the base sections of the first plurality of capacitive electrodes are arranged in parallel, 
 further comprising a second layer of electrodes arranged perpendicular to the base frame sections of said capacitive electrodes of the first layer, wherein first and second layer are insulated by a substrate, 
 wherein center electrodes of the second layer electrodes comprise a rectangular base section substantially extending from a left to a right side along a length of the sensing area and a plurality of finger sections from a top and bottom side of the rectangular base section, 
 wherein top and bottom electrode of the second layer electrodes comprise a rectangular base section substantially extending from the left to the right side along the length of the sensing area and a plurality of finger sections from a top or bottom side, respectively, and 
 wherein adjacent electrodes of the second layer are arranged in an interdigital fashion with respect to the finger sections of the second layer electrodes, and 
 wherein each capacitive electrode is further configured to be connected with a connecting line and wherein the connecting line extends through a center of the base frame section from a top to a bottom of the base frame section along the width of the sensing area. 
 
     
     
       12. The capacitive sensor structure of  claim 1 , further comprising a most right and a most left electrode within the first layer each comprising an electrode base frame section and a plurality of cross frame sections, wherein the plurality of cross frame sections cross the respective base frame asymmetrically.